Postural imbalance can result from various vestibular (central and peripheral), neurological, orthopedic, and vascular disorders, as well as sensory conflicts, traumatic brain injuries, infections, medications, and aging. There are physical, emotional, and monetary costs associated with balance impairments and the falls that typically ensue from acute or chronic bouts of instability. Thirty-five percent of U.S. citizens over the age of 40 have vestibular dysfunction, and each year approximately 16 million new vestibular patients are diagnosed. Sensory substitution is a technique of augmenting or replacing compromised sensory information. In the context of sensory-based balance impairments, a sensory substitution device provides cues of body motion to supplement an individual's intact sensory systems, using motion sensors and an appropriate feedback display. Growing evidence suggests that sensory substitution can be used to improve real-time postural stability as well as provide persistent improvements over time periods of minutes to hours following a small number of rehabilitative training sessions. However, sustainable quality-of-life improvement requires retention of balance improvement on the order of weeks to months. While case study results from a single subject participating in a large number of training sessions showed improvements that lasted up to 8 weeks, no systematic studies have been performed to determine the influence of sensory substitution training on long-term retention following a large number of vestibular balance rehabilitation sessions. The specific aim of this research is to evaluate the persistence of balance improvement for persons with bilateral vestibular hypofunction receiving vibrotactile sensory substitution during 18 sessions of standard vestibular rehabilitation therapy (VRT) exercises, in comparison to those receiving standard VRT exercises alone.